[TheForge] more than you ever wanted to know about hot vs cold rolled

[Grant Neil Sarver]

Although the term "cold rolled" is in common usage to refer to cold finished
bar I don't believe any of it is actually rolled. The only mill product that
is truly cold rolled is is cold rolled sheet. Cold finished bar is all drawn
to size just like wire. Hot rolled bar is  generally annealed then pickeled
and oiled. From there it goes to the draw shop where it is pulled through a
hole in a carbide die. The hole is commonly 1/16 inch smaller than the
original bar. The resulting bar is very close in size and almost perfectly
straight due to the enormous tension it's under in pulling. Some very
interesting shapes can be produced by this method too. I've had bar drawn for
me in special alloys and had to buy 13/16 hex  in order to produce 3/4 hex
cold drawn. The reason 1018 is used in cold drawn merchant bar is that the
quality (tensile strength, yeild strengh and elongation) is much more
consistant than any A-36. 1018 and any number of "mild" grades can be had from
the mill or from a steel broker.

grant (NAKED ANVIL)